226 H. E. Eoworth—A Great Fost-Qlacial Flood. 



flints with sharp edges showing they have not been waterworn, the 

 presence in large numbers of intact land shells which are essentially 

 fragile, the similar presence of remains of land animals, and of the 

 works of man, all point in one direction only, and prechade the 

 notion that these loams are either marine, lacustrine, or fluviatile. 

 In regard to their texture, the evidence points the same way, and 

 the following sentence of Mr. Belt, arguing against their fluviatile 

 origin, seems to contain a just conclusion; he says, "The brick 

 clay that overlies the gravel is considered by Professor Prestwich 

 to be inundation mud. We have silty deposits now forming, or 

 lately formed, on the low flats adjoining the Thames : they consist 

 of dark blue clay, with remains of vegetation and land and fresh- 

 water shells. Sometimes peat beds occur. The brick clay, on the 

 other hand, is a homogeneous unstratified brown clay, without any 

 organic remains." — Quart. Journal of Science, vol. viii. N.S. p. 346. 



The view as to the origin of the loams, which seems supported 

 by overwhelming evidence, is the one maintained by Professor 

 Ramsay when Mr. Kingsmill's paper on the Loess was read before 

 the Geological Society, namely, that the Brick-earths of our southern 

 counties and the loams of Picardj' are of subaerial origin. The beds 

 have all the character of subaerial beds, and I have very little doubt 

 that these loams represent the old land surface upon which the 

 Mammoth and his companions lived. If it be not so, the burden 

 of proof seems most certainly to lie upon those who maintain the 

 contrary. 



Having considered the origin of the loam, we may now turn 

 to what more immediately concerns us, namely, its distribution. 

 There is one remarkable feature about it to which attention has 

 not been sufficiently attracted. The Diluvium in France and in 

 Belgium and the Brick-earths in South Britain agree in this cardinal 

 factor — that they are all separable into two well-marked forms : 

 one stratum bearing all the marks of being largely in situ and un- 

 disturbed ; and the second stratum being markedly disturbed. 



In regard to the Diluvium of the French writers, the fact has long 

 been familiar. One form of it is known as diluvium gris, while the 

 other one is called diluvium rouge. For a long time a dispute pre- 

 vailed among French writers as to whether the two are essentially 

 distinct, or whether the diluvium rouge is not an altered and sophis- 

 ticated layer of the grey diluvium; its ruhification, to introduce a 

 French phrase of M. Vanden Broeck, being due to the iniiltration of 

 water containing acids. The best opinion now, and the one gene- 

 rally held, is that, although there is a certain difference between the 

 two strata, the pebbles in the diluvium rouge being more rolled than 

 in the other, while there is a greater scarcity in it of those mam- 

 malian remains which characterize so richly the diluvium gris, that 

 nevertheless there is a complete continuity between the two, and that 

 they belong essentially to one horizon. 



The diluvium gris, with its numerous remains of a land fauna 

 and abundant land shells, represents the old land surface upon 

 which the Mammoths lived, in situ, and largely undisturbed. It 



